Worse than we thought: Antarctic vulnerability to climate change

From the “Antarctic ice is normal now but just you wait” department….

S_daily_extent_hires S_stddev_timeseries

Above:  most recent data from NSIDC.

….and the UNIVERSITY OF EDINBURGH:


Antarctica’s past shows region’s vulnerability to climate change

Fresh understanding of West Antarctica has revealed how the region’s ice sheet could become unstable in a warming world.

Scientists studying the region’s landscape have determined how it reacted to a period of warming after the coldest point of the most recent Ice Age, some 21,000 years ago.

As the Earth warmed, the West Antarctic Ice Sheet reached a tipping point after which it thinned relatively quickly, losing 400m of thickness in 3,000 years, researchers found. This caused sea levels around the world to increase by up to two metres.

Their findings will help scientists understand how the region may behave under future environmental change.

Researchers studied peaks protruding through ice in the Ellsworth Mountains on the Atlantic coast of the continent, to determine how the land’s ice coverage has changed since the Ice Age.

Scientists used chemical technology – known as exposure dating – to calculate how long rocks on the mountainside had been free from ice cover. They used their results to determine how the height of the ice sheet had changed over thousands of years.

They found that this sector of the ice sheet – close to the Weddell Sea – had remained covered with thick ice long after other parts of the Earth had begun to emerge from the Ice Age. Heavier snowfall, caused by warmer air, probably helped to maintain the ice thickness.

As the seas warmed, ice at the coast began to be lost to the oceans. Eventually, a tipping point was reached after which the ice sheet thinned more rapidly, retreating inland.

The study, carried out in collaboration with Northumbria University, Newcastle University and the Scottish Universities Environmental Research Centre, was published in Nature Communications. It was supported by the Natural Environment Research Council.

Dr Andrew Hein of the University of Edinburgh’s School of GeoSciences, who jointly led the study, said: “West Antarctica has undergone complex changes since the last Ice Age, and it quickly became unstable – similar processes may dominate the future of the region in a warmer world.”

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64 thoughts on “Worse than we thought: Antarctic vulnerability to climate change

    • losing 400m of thickness in 3,000 years,…from a friggin ice age
      Almost all of that should be gone already

  1. 1) It’s a single point, yet they are claiming to represent all of Antarctica.
    2) 2 meters over 3000 years. That’s less than 7 millimeters per year.
    3) Is exposure dating actually accurate enough to make these claims?
    4) Does the top few feet of glacier erode the rock enough so that this exposure clock actually starts when the glacier uncovers the rock in question?
    5) If the seas were warming and the extent of sea ice decreasing, then the humidity available for snow fall would be increasing, have they factored increased snow fall into their “exposure” calculations?

    • “2) 7 millimeters a year”
      You don’t think that’s an issue that’s and inch every 3.5 years or so. Heck in thirty years I would have to raise my sea wall more than half a foot just to stay even.
      (sarc off now)

      • Don’t forget the “up to” weasel language; that means the rise might have been significantly less. As a chemistry major, I don’t think even once in all my science education did the lab instructions include “up to” (or “may have” or “could” etc.). Science has no use for such vagueness unless it is discussing alternate, unproven theories or results with inherent error margins that prevent definitive statements (and thus prevent proof).

    • Please check my math, but it’s even worse than they thought. 2 meters (2000 mm)/3000 years is only 0.7 mm/yr.

      • 400 meters is the ice thickness in Antarctica. The melt cover the entire ocean contributing 2 meters. Over a period of 3000 years.

      • As the Earth warmed, the West Antarctic Ice Sheet reached a tipping point after which it thinned relatively quickly, losing 400m of thickness in 3,000 years, researchers found. This caused sea levels around the world to increase by up to two metres.
        400m of ice melted. Sea level rose two meters (2,000mm).
        Science is hard.

      • KRM,
        Sorry, I may not have been clear. I was referring to the 2m sea level rise referenced in the post and to which I think MarkW was referring.

  2. 6) We know from modern studies that the edges of the Antarctic continent are more impacted by changes in sea temperature than is the interior.

  3. Anybody look at the NSIDC artic map? it looks like some one cut a piece of ice out the same size and shape as Great Britton, wonder what that could mean? Spooky maybe its a sign.

  4. My word, with the removal of that much ice, the entire continent might tip over. Just think of what would happen to the penguin rookeries! Opus will be the new polar bear.

  5. Hi Mark W, 2M = 2000mm /3000yrs =0.7mm/yr exactly. But given variability in the weather and climate not bang on every year. Cheers from downunder

  6. 1. A picture of sea ice extent doesn’t have anything to do with anything.
    2. Antarctica isn’t losing ice.
    https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses
    A new NASA study says that an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers.
    The research challenges the conclusions of other studies, including the Intergovernmental Panel on Climate Change’s (IPCC) 2013 report, which says that Antarctica is overall losing land ice.
    According to the new analysis of satellite data, the Antarctic ice sheet showed a net gain of 112 billion tons of ice a year from 1992 to 2001. That net gain slowed to 82 billion tons of ice per year between 2003 and 2008.

    3. Antarctica really isn’t losing land ice:
    http://tycho.usno.navy.mil/lod.1973-may2015.jpg
    http://spacemath.gsfc.nasa.gov/earth/6Page58.pdf
    The length of day should be getting 0.24 milliseconds longer each decade, and that rate should be higher and accelerating if the Antarctic was melting. Clearly that isn’t happening.as illustrated in the above chart.

  7. Have they considered that the loss of ice in West Antarctica is mainly a consequence of rising sea level rather than a cause of it? If sea level rises due to melting of land-based ice in the Northern Hemisphere (as it did), then the water covering the Antarctic continental shelf gets deeper. This causes a retreat of Antarctic glacier and ice-shelf grounding lines, which destabilises the land-based ice sheet somewhat. So loss of ice mass in Antarctica can, at least partially, be a passive response to Northern Hemisphere ice-loss. Ice loss in Antarctica is not just controlled by the warmth of the climate around the fringes of the continent. Further, the 2 to 3 m rise in sea level referred to in the above article was almost certainly mainly produced as a feedback to events in the Northern Hemisphere. The ultimate cause is probably not to be found either in, or around Antactica.
    So the current and future sensitivity of West Antarctica to another episode of massive ice loss is probably tied directly to the stability of the Greenland icesheet.

    • Our Director of Public Prosecutions, equivalent to a DA, hasn’t quite got round to advocating the legal harassment of those who dare to question the consensus – yet.

    • Aus has some well supported by Govvy media like ABC
      as example today
      they run an item saying the ice shelf Larsen developed a further 22km crack over winter
      doom glom tradgedy was hoped for BY the mediashill, the “spurt” t least was honest enough to admit shelf ice doesnt rise sea levels
      but
      then just had to add the “fear” that once the shelf breaks off it might allow land ice to slip off to sea faster.
      nearly smashed the radio!

  8. I find it interesting that any of these types of studies present an ‘elephant in the room’ as they look to the past. We see our little slow warming out of the LIA is nothing compared to all manner of natural variation in the past.
    But, with a straight face they use paleo climate to try to increase public concern of man caused warming.
    With a straight face and actual science behind them, they should be helping Canadians and Britains to figure out where to move their population when Ice Age conditions inevitably return. That’s a real and looming climate concern yet ‘the science is settled’ crowd still cannot explain the reasons that form the upper and lower bounds the climate has been oscillating between in the recent geologic past.
    So predictable…..

  9. “Scientists studying the region’s landscape have determined how it reacted to a period of warming after the coldest point of the most recent Ice Age, some 21,000 years ago.”
    earliest attempts at a bronze age?

  10. “As the Earth warmed, the West Antarctic Ice Sheet reached a tipping point after which it thinned relatively quickly, losing 400m of thickness in 3,000 years, researchers found. This caused sea levels around the world to increase by up to two metres…”

    21,000 years ago, the Earth warmed up enough that West Antarctica lost 400 meters, (437 yards) of ice thickness; causing the sea level to rise 2 meters?
    So much for this year being the ‘hottest ever!’
    And West Antarctica lost 400m of ice… From on top where the warm air collects?
    Was West Antarctica so removed or isolated from Antarctica that West Antarctica wilted while Antarctica froze?
    Just how warm, (hot?), did West Antarctica allegedly become?

    “…Researchers studied peaks protruding through ice in the Ellsworth Mountains on the Atlantic coast of the continent, to determine how the land’s ice coverage has changed since the Ice Age.
    Scientists used chemical technology – known as exposure dating – to calculate how long rocks on the mountainside had been free from ice cover. They used their results to determine how the height of the ice sheet had changed over thousands of years.
    They found that this sector of the ice sheet – close to the Weddell Sea – had remained covered with thick ice long after other parts of the Earth had begun to emerge from the Ice Age. Heavier snowfall, caused by warmer air, probably helped to maintain the ice thickness…”

    Now, West Antarctica has peaks that remained covered by ice, “long after other parts of the Earth had begun to emerge from the Ice Age”.
    Which is it!?
    Two meters of sea level increase due to 400m of ice melt or less ice melt?
    Heavier snowfall? Backed up by ice core analysis? Or solely guessed by rock exposure?
    What happens when a rock is covered/uncovered repeatedly over millennia?

    “…As the seas warmed, ice at the coast began to be lost to the oceans. Eventually, a tipping point was reached after which the ice sheet thinned more rapidly, retreating inland…”

    Horrors! The dreaded tipping point!
    Which means exactly what? As in exactly what happened that makes it a tipping point?
    “As the seas warmed…”
    Nice generic statement. Without substance or meaning.
    “The ice sheet thinned rapidly…”
    Given that Antarctica is frequently/annually surrounded by sea ice, just what does this vague bit of wordplay actually mean?
    Summation:
    Another bafflegab piece throwing around loose pieces of research interspersed with long leaps in logic and incredible assumptions.
    What I find myself wondering, is if all of this ice melted from the tops of Antarctica, just what does losing so much Holocene ice do to ice core reconstructions.

    • “Given that Antarctica is frequently/annually surrounded by sea ice, just what does this vague bit of wordplay actually mean?”
      In this case about 130 millimeter (five inches) of thinning per year, which is rapid for a glacier, and equal to a sea-level rise of about 0.5-0.7 millimeters per year. However most of the rise was probably near the beginning and the end of the period. The sea-ice around Antarctica is completely irrelevant.

    • tty is back again, lost, wandering making pointless and often highly erroneous comments.
      Hey tty, maybe you should read the whole article above!
      It is not a discussion about today’s ice, or the alarmist fabrications regarding virtually non-existent melting.
      The discussion covers 21,000 years of Antarctic ice. Along with chemical surface testing of exposed rocks that reveal all.
      Though, I suppose it would be too much to hope you actually learn something from reading the article.

      • ATheoK
        I did read the paper. You clearly didn’t. Yes, it is concerned with the interval since the LGM, but the main lowering of the glacier level happened 6,500-3,500 BP.
        By the way exposure dating is based on radionuclides, not chemistry.

      • Oh Dear!
        tty completely forgot that he started this comment series with his fallacious claim about current Antarctic ice loss.
        The old strawman argument; when a response is tendered, tty argues a completely different point.
        So sad tty, so dismal, so shallow.

        “…Whole rock samples were crushed and sieved to obtain the 250–710 μm fraction. Be and Al were selectively extracted from the quartz component of the whole-rock sample…”

        Apparently, tty never took chemistry either.
        I wonder just how all of those radio-nuclides were extracted and concentrated without chemistry…
        Typical CAGW alarmist type education tty, zero understanding of science, especially the physical sciences; e.g. geology, chemistry, physics.

        “…In this study, we favour the youngest exposure age at each altitude to best represent the elevation of the ice surface at the time…”

        “…We sampled the freshest-appearing, quartz-bearing, brick-sized clasts resting on flat bedrock to minimize problems of post-depositional movement and self-shielding…”

        “When considering all sites together, the modelling suggests a lower and linear thinning rate of 8.8±0.2 cm a−1, but initiated a little earlier at about 8.5–9 ka. The exercise demonstrates that our conclusion of a mid-Holocene pulse of thinning, which was complete by 3.5 ka, is not sensitive to our interpretation based on the youngest exposure. In Supplementary Fig. 4, we increase the range to include all 10Be exposure ages <15 ka, and then with three clear outliers (3σ) removed to obtain a linear regression through all deglacial exposure ages. The model suggests the onset of initial deglaciation was at 9–10.5 ka, with a lower average thinning rate of 8.1±0.2 cm a−1."

        The research comes off far worse in the full paper.
        &bull Now it is obvious that they cherry picked samples.
        &bull Made giant leaps in assumptions, without evidence. What evidence they do have, they collected or generated after settling on their findings first.
        &bull Used models to flesh out and bless their whole preconceived morass of assumptions.

        “…Blue-ice moraines form on the windswept ice surface at the foot of the mountains and remnants of earlier blue-ice moraines occur up to 650 m above the present ice surface. Little-weathered blue-ice deposits extend up to 475 m above the ice surface and mark the decline in ice surface elevation since the LGM…”

        Don’t you like that beginning assumption?
        Ice stuck to the side of mountains is proof of previous maximum height ice sheets? Quite a leap there.
        “On top of old Smokey,
        All covered with snow,
        I lost my true lover,
        For courting too slow”

      • ATheoK
        I have never made any claim whatsoever about current ice-loss, if any. My figures was for the main thinning period 6.5-3.5 KA BP. Perhaps I should have stated this explicitly, but since this whole thread is about this thinning episode it seemed rather unnecessary. But not when trying to explain something to you apparently.
        “I wonder just how all of those radio-nuclides were extracted and concentrated without chemistry…”
        It is done by accelerator mass spectrometry (AMS), but you are welcome to try to isolate and measure 10Be by chemical methods. Good Luck!
        “Typical CAGW alarmist type education tty, zero understanding of science, especially the physical sciences; e.g. geology, chemistry, physics.”
        Amusingly enough I majored in physics.
        “Ice stuck to the side of mountains is proof of previous maximum height ice sheets?”
        Moraine consists of ROCKS not ice. And yes, the altitude of lateral moraines/trimlines do indicate the maximum vertical extent of glaciation. You seem to be rather remarkably ignorant about geology by the way.

      • So sad tty, you’re still confused.

        “…It is done by accelerator mass spectrometry (AMS), but you are welcome to try to isolate and measure 10Be by chemical methods. Good Luck!…”

        And we suppose all of those beryllium atoms just happened to be in a nice concentrated solution for testing in the mass spectrometer?
        Just picked up on those loose quartzite surface rocks?

        “…Moraine consists of ROCKS not ice…”

        Really? And just how do those silly twits posing as Antarctic researchers just happen to know they are “blue ice moraines”?
        Remember?

        “…Blue-ice moraines form on the windswept ice surface at the foot of the mountains and remnants of earlier blue-ice moraines occur up to 650 m above the present ice surface. Little-weathered blue-ice deposits extend up to 475 m above the ice surface and mark the decline in ice surface elevation since the LGM…”

        “Itty bitty little blue ice deposits.”
        “Remnants of earlier blue-ice moraines”
        Definition of moraine
        1: an accumulation of earth and stones carried and finally deposited by a glacier”
        To have a moraine, requires accumulated snow, forming into moving ice or glacier.
        Melting or sublimation of the ice causes material picked up by the glacier to fall; especially at glacier terminations.
        A moraine is chiefly dirt, rocks, soil and debris. The debris often includes ice if the weather is cold enough.
        Oddly, Antarctic weather is generally more than cold enough.
        From itty bitty blue ice deposits and remnants of earlier blue ice moraines, the researchers immediately jump to Antarctic ice levels 400m higher.
        Amazingly, moraines, lateral or not, indicate moving ice, i.e. glaciers, not previous heights of total ice flowing away from the mountains.
        All that is required is sufficient accumulation of snow to form a glacier. When enough snow accumulates, ice forms and eventually the ice begins to flow, grating up debris.
        Discovery of evidence for glaciers does not equate to assumptions for 400m of ice.
        Ice covered rocks are not evidence of 400m of ice. Instead they are evidence that for significant periods of time, ice covered them…

        tty states: “You seem to be rather remarkably ignorant about geology by the way.”

        And you assume to lecture others about geology?
        Suuure tty…
        Excuse me, while I guffaw loudly.

  11. Always interesting that WEST Antarctic goes under the microscope. The obvious question to ask is why the sea surface temperatures are anomalously high around that peninsula poking out into the sea. And why is that (non-representative) peninsula there in the first place? The obvious answer is that it was formed by a chain of volcanoes, with many new young active ones being recently discovered beneath the waves.
    http://www.coolantarctica.com/Antarctica%20fact%20file/science/Antarctica-warming-2004.jpg
    Might explain a few things.

  12. “similar processes may dominate the future of the region in a warmer world.”
    There’s that lovely qualifier again; MAY. Yeah. I may win the lottery tomorrow and all the climate scammers may be thrown in jail. When did “science” start using such weasel words?

  13. “similar processes may dominate the future of the region in a warmer world.”
    There’s that weasel word again; MAY. Yeah. I MAY win the lottery tomorrow and all the climate scammers MAY get thrown in jail. When did “science” start using such weasel words?

  14. ““West Antarctica has undergone complex changes since the last Ice Age, and it quickly became unstable – similar processes may dominate the future of the region in a warmer world.”
    If this is about the Antarctic Peninsula, the one that extends almost to South America, why would the region not be vulnerable during an interglacial?
    After all, the Peninsula is as close to the Equator as Iceland.and the Bering Strait Alaska.
    This part of Alaska is not covered by a glacier.
    https://www.google.com/maps/@65.6428079,-167.620477,40962m/data=!3m1!1e3

  15. From the “Antarctic ice is normal now but just you wait” department….
    – highly addictive potentials !

  16. “West Antarctica has undergone complex changes since the last Ice Age, and it quickly became unstable – similar processes may dominate the future of the region in a warmer world.”
    ______________________________________
    Said “future” is the remaining time of “our” interglacial. Only fact we know for sure.

  17. It is interesting to note that the same research group published another paper, also in Nature Communications, about their research in the Ellsworth Range a few months ago. Somehow it didn’t make it into the MSM. The title tells the story why:
    “Evidence for the stability of the West Antarctic Ice Sheet divide for 1.4 million years”
    http://www.nature.com/articles/ncomms10325
    This latest paper is
    “Mid-Holocene pulse of thinning in the Weddell Sea sector of the West Antarctic ice sheet”
    http://www.nature.com/articles/ncomms12511
    I recommend that you read it (it isn’t very difficult), since the press release seems to have been written to be intentionally misleading (as press releases quite often are). For example it is quite impossible to guess from the press-release when this thinning happened (6,500-3,500 years ago).
    I have been following this group, and in my opinion they are producing good science and their papers only contain the minimum obeisances to CAGW required for publication.

  18. Just clarify, are we talking about cold ice, which results from Ice Ages and the like, or warm ice, which (like warm snow) results from Man Made Global Warming?

  19. I don’t think it is possible for us to go for six months without some article about some ice shelf melting or threatening to break away in the Antarctic getting into the regular media. It all gets to be very redundant and hard for even those of us interested to not begin to see it as more blah blah blah. If something really big having global implications did happen it would be hard for them to get the attention of the layman because of their constant cries of wolf over the last decades. The average person would see the news and think ‘Same S%!t different day. So what’s new?’ And to be quite frank that is exactly my reaction to this article.

  20. The “rapid” melting back then caused 2m sea level rise in 3,000 years. Yikes! so fast! we are going to drown! Oh….3,000 years…never mind…

  21. Has there ever been a paper showing an unconformity in Antarctic ice layers shown in drill cores? If ice is lost from the land based portion, an unconformity is a plausible first signal. BTW it would play hell with chronologies.
    If no unconformity has been found, there is no point in hypotheses about ice loss from melting.
    Geoff

    • Ice doesn’t melt in Antarctica. It calves into the sea or sublimates.
      In Greenland “unconformities” (melt layers) occasionally occur, especially in the south. In Antarctica they are absent or extremely rare.They certainly never occur up near the ice-divides where ice-cores are drilled.
      The lowered level of the glacier in this case was entirely due to increased calving (marine draw-down).
      Ice in Antarctica does sublimate, i e turn directly from ice to water vapor. This paper is based on dating “blue-ice moraines” left by such sublimation.

    • PS
      Perhaps I should have mentioned that melting does occur in some areas at the bottom of the ice-sheet by geothermal heat. That is the reason that there are lakes under the ice in some areas.

      • TTY,
        Thank you. All that you commented has been known for a long time.
        This is what I am getting at. If Antarctic ice is going to contribute to ocean level rise where does the added water come from?
        For ice above land, sublimation is one way. Has it been measured accurately? Another way is basal meltwater, but it is hardly related to CO2. Another path is the toothpaste method, squeezing ice into the sea, but it’s importance is limited to the relatively small area of glaciers.
        Of course, melting of ice now floating on water does not much affect levels, Avogadro.
        When there are several theoretical ways for ocean levels to be affected, often one or two might dominate. Which are the major postulated players and how well are they quantified?
        Yes, I am aware of glaciers on bedrock in shallow water and some of their complications.
        Geoff

      • Geoff Sherrington on August 23, 2016 at 4:41 pm
        TTY,
        Thank you. All that you commented has been known for a long time.
        _______________________________________
        Yep, but – wrong adress. Please tell that Obama, Merkel and IPCC.
        They should know too.

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